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<div class="title">TensorDeviceThreadPool.h</div>  </div>
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<div class="contents">
<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="comment">// This file is part of Eigen, a lightweight C++ template library</span></div>
<div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="comment">// for linear algebra.</span></div>
<div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment">// Copyright (C) 2014 Benoit Steiner &lt;benoit.steiner.goog@gmail.com&gt;</span></div>
<div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment">// This Source Code Form is subject to the terms of the Mozilla</span></div>
<div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment">// Public License v. 2.0. If a copy of the MPL was not distributed</span></div>
<div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="comment">// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.</span></div>
<div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160; </div>
<div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="preprocessor">#if defined(EIGEN_USE_THREADS) &amp;&amp; !defined(EIGEN_CXX11_TENSOR_TENSOR_DEVICE_THREAD_POOL_H)</span></div>
<div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="preprocessor">#define EIGEN_CXX11_TENSOR_TENSOR_DEVICE_THREAD_POOL_H</span></div>
<div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160; </div>
<div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="preprocessor">#include &quot;./InternalHeaderCheck.h&quot;</span></div>
<div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160; </div>
<div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="keyword">namespace </span><a class="code" href="namespaceEigen.html">Eigen</a> {</div>
<div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160; </div>
<div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="comment">// Runs an arbitrary function and then calls Notify() on the passed in</span></div>
<div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="comment">// Notification.</span></div>
<div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> Function, <span class="keyword">typename</span>... Args&gt; <span class="keyword">struct </span>FunctionWrapperWithNotification</div>
<div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;{</div>
<div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;  <span class="keyword">static</span> <span class="keywordtype">void</span> run(Notification* n, Function f, Args... args) {</div>
<div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;    f(args...);</div>
<div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;    <span class="keywordflow">if</span> (n) {</div>
<div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;      n-&gt;Notify();</div>
<div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160;    }</div>
<div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;  }</div>
<div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;};</div>
<div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160; </div>
<div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> Function, <span class="keyword">typename</span>... Args&gt; <span class="keyword">struct </span>FunctionWrapperWithBarrier</div>
<div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;{</div>
<div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;  <span class="keyword">static</span> <span class="keywordtype">void</span> run(Barrier* b, Function f, Args... args) {</div>
<div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;    f(args...);</div>
<div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;    <span class="keywordflow">if</span> (b) {</div>
<div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160;      b-&gt;Notify();</div>
<div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;    }</div>
<div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;  }</div>
<div class="line"><a name="l00037"></a><span class="lineno">   37</span>&#160;};</div>
<div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160; </div>
<div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SyncType&gt;</div>
<div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;<span class="keyword">static</span> EIGEN_STRONG_INLINE <span class="keywordtype">void</span> wait_until_ready(SyncType* n) {</div>
<div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;  <span class="keywordflow">if</span> (n) {</div>
<div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;    n-&gt;Wait();</div>
<div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;  }</div>
<div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;}</div>
<div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160; </div>
<div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;<span class="comment">// An abstract interface to a device specific memory allocator.</span></div>
<div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;<span class="keyword">class </span>Allocator {</div>
<div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160; <span class="keyword">public</span>:</div>
<div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;  <span class="keyword">virtual</span> ~Allocator() {}</div>
<div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160;  <span class="keyword">virtual</span> <span class="keywordtype">void</span>* allocate(<span class="keywordtype">size_t</span> num_bytes) <span class="keyword">const</span> = 0;</div>
<div class="line"><a name="l00051"></a><span class="lineno">   51</span>&#160;  <span class="keyword">virtual</span> <span class="keywordtype">void</span> deallocate(<span class="keywordtype">void</span>* buffer) <span class="keyword">const</span> = 0;</div>
<div class="line"><a name="l00052"></a><span class="lineno">   52</span>&#160;};</div>
<div class="line"><a name="l00053"></a><span class="lineno">   53</span>&#160; </div>
<div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;<span class="comment">// Build a thread pool device on top the an existing pool of threads.</span></div>
<div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160;<span class="keyword">struct </span>ThreadPoolDevice {</div>
<div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;  <span class="comment">// The ownership of the thread pool remains with the caller.</span></div>
<div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;  ThreadPoolDevice(ThreadPoolInterface* pool, <span class="keywordtype">int</span> num_cores, Allocator* allocator = <span class="keyword">nullptr</span>)</div>
<div class="line"><a name="l00058"></a><span class="lineno">   58</span>&#160;      : pool_(pool), num_threads_(num_cores), allocator_(allocator) { }</div>
<div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160; </div>
<div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span>* allocate(<span class="keywordtype">size_t</span> num_bytes)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;    <span class="keywordflow">return</span> allocator_ ? allocator_-&gt;allocate(num_bytes)</div>
<div class="line"><a name="l00062"></a><span class="lineno">   62</span>&#160;        : internal::aligned_malloc(num_bytes);</div>
<div class="line"><a name="l00063"></a><span class="lineno">   63</span>&#160;  }</div>
<div class="line"><a name="l00064"></a><span class="lineno">   64</span>&#160; </div>
<div class="line"><a name="l00065"></a><span class="lineno">   65</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> deallocate(<span class="keywordtype">void</span>* buffer)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160;    <span class="keywordflow">if</span> (allocator_) {</div>
<div class="line"><a name="l00067"></a><span class="lineno">   67</span>&#160;      allocator_-&gt;deallocate(buffer);</div>
<div class="line"><a name="l00068"></a><span class="lineno">   68</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00069"></a><span class="lineno">   69</span>&#160;      internal::aligned_free(buffer);</div>
<div class="line"><a name="l00070"></a><span class="lineno">   70</span>&#160;    }</div>
<div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;  }</div>
<div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160; </div>
<div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;    EIGEN_STRONG_INLINE <span class="keywordtype">void</span>* allocate_temp(<span class="keywordtype">size_t</span> num_bytes)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;    <span class="keywordflow">return</span> allocate(num_bytes);</div>
<div class="line"><a name="l00075"></a><span class="lineno">   75</span>&#160;  }</div>
<div class="line"><a name="l00076"></a><span class="lineno">   76</span>&#160; </div>
<div class="line"><a name="l00077"></a><span class="lineno">   77</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> deallocate_temp(<span class="keywordtype">void</span>* buffer)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;    deallocate(buffer);</div>
<div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;  }</div>
<div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160; </div>
<div class="line"><a name="l00081"></a><span class="lineno">   81</span>&#160;  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Type&gt;</div>
<div class="line"><a name="l00082"></a><span class="lineno">   82</span>&#160;  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Type get(Type data)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00083"></a><span class="lineno">   83</span>&#160;    <span class="keywordflow">return</span> data;</div>
<div class="line"><a name="l00084"></a><span class="lineno">   84</span>&#160;  }</div>
<div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160; </div>
<div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> memcpy(<span class="keywordtype">void</span>* dst, <span class="keyword">const</span> <span class="keywordtype">void</span>* src, <span class="keywordtype">size_t</span> n)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00087"></a><span class="lineno">   87</span>&#160;<span class="preprocessor">#ifdef __ANDROID__</span></div>
<div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;    ::memcpy(dst, src, n);</div>
<div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;<span class="preprocessor">#else</span></div>
<div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;    <span class="comment">// TODO(rmlarsen): Align blocks on cache lines.</span></div>
<div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;    <span class="comment">// We have observed that going beyond 4 threads usually just wastes</span></div>
<div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;    <span class="comment">// CPU cycles due to the threads competing for memory bandwidth, so we</span></div>
<div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;    <span class="comment">// statically schedule at most 4 block copies here.</span></div>
<div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;    <span class="keyword">const</span> <span class="keywordtype">size_t</span> kMinBlockSize = 32768;</div>
<div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;    <span class="keyword">const</span> <span class="keywordtype">size_t</span> num_threads = CostModel::numThreads(n, TensorOpCost(1.0, 1.0, 0), 4);</div>
<div class="line"><a name="l00096"></a><span class="lineno">   96</span>&#160;    <span class="keywordflow">if</span> (n &lt;= kMinBlockSize || num_threads &lt; 2) {</div>
<div class="line"><a name="l00097"></a><span class="lineno">   97</span>&#160;      ::memcpy(dst, src, n);</div>
<div class="line"><a name="l00098"></a><span class="lineno">   98</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00099"></a><span class="lineno">   99</span>&#160;      <span class="keyword">const</span> <span class="keywordtype">char</span>* src_ptr = <span class="keyword">static_cast&lt;</span><span class="keyword">const </span><span class="keywordtype">char</span>*<span class="keyword">&gt;</span>(src);</div>
<div class="line"><a name="l00100"></a><span class="lineno">  100</span>&#160;      <span class="keywordtype">char</span>* dst_ptr = <span class="keyword">static_cast&lt;</span><span class="keywordtype">char</span>*<span class="keyword">&gt;</span>(dst);</div>
<div class="line"><a name="l00101"></a><span class="lineno">  101</span>&#160;      <span class="keyword">const</span> <span class="keywordtype">size_t</span> blocksize = (n + (num_threads - 1)) / num_threads;</div>
<div class="line"><a name="l00102"></a><span class="lineno">  102</span>&#160;      Barrier barrier(<span class="keyword">static_cast&lt;</span><span class="keywordtype">int</span><span class="keyword">&gt;</span>(num_threads - 1));</div>
<div class="line"><a name="l00103"></a><span class="lineno">  103</span>&#160;      <span class="comment">// Launch the last 3 blocks on worker threads.</span></div>
<div class="line"><a name="l00104"></a><span class="lineno">  104</span>&#160;      <span class="keywordflow">for</span> (<span class="keywordtype">size_t</span> i = 1; i &lt; num_threads; ++i) {</div>
<div class="line"><a name="l00105"></a><span class="lineno">  105</span>&#160;        enqueue_with_barrier(&amp;barrier, [n, i, src_ptr, dst_ptr, blocksize] {</div>
<div class="line"><a name="l00106"></a><span class="lineno">  106</span>&#160;          ::memcpy(dst_ptr + i * blocksize, src_ptr + i * blocksize,</div>
<div class="line"><a name="l00107"></a><span class="lineno">  107</span>&#160;                   numext::mini(blocksize, n - (i * blocksize)));</div>
<div class="line"><a name="l00108"></a><span class="lineno">  108</span>&#160;        });</div>
<div class="line"><a name="l00109"></a><span class="lineno">  109</span>&#160;      }</div>
<div class="line"><a name="l00110"></a><span class="lineno">  110</span>&#160;      <span class="comment">// Launch the first block on the main thread.</span></div>
<div class="line"><a name="l00111"></a><span class="lineno">  111</span>&#160;      ::memcpy(dst_ptr, src_ptr, blocksize);</div>
<div class="line"><a name="l00112"></a><span class="lineno">  112</span>&#160;      barrier.Wait();</div>
<div class="line"><a name="l00113"></a><span class="lineno">  113</span>&#160;    }</div>
<div class="line"><a name="l00114"></a><span class="lineno">  114</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00115"></a><span class="lineno">  115</span>&#160;  }</div>
<div class="line"><a name="l00116"></a><span class="lineno">  116</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> memcpyHostToDevice(<span class="keywordtype">void</span>* dst, <span class="keyword">const</span> <span class="keywordtype">void</span>* src, <span class="keywordtype">size_t</span> n)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00117"></a><span class="lineno">  117</span>&#160;    memcpy(dst, src, n);</div>
<div class="line"><a name="l00118"></a><span class="lineno">  118</span>&#160;  }</div>
<div class="line"><a name="l00119"></a><span class="lineno">  119</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> memcpyDeviceToHost(<span class="keywordtype">void</span>* dst, <span class="keyword">const</span> <span class="keywordtype">void</span>* src, <span class="keywordtype">size_t</span> n)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00120"></a><span class="lineno">  120</span>&#160;    memcpy(dst, src, n);</div>
<div class="line"><a name="l00121"></a><span class="lineno">  121</span>&#160;  }</div>
<div class="line"><a name="l00122"></a><span class="lineno">  122</span>&#160; </div>
<div class="line"><a name="l00123"></a><span class="lineno">  123</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> memset(<span class="keywordtype">void</span>* buffer, <span class="keywordtype">int</span> c, <span class="keywordtype">size_t</span> n)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00124"></a><span class="lineno">  124</span>&#160;    ::memset(buffer, c, n);</div>
<div class="line"><a name="l00125"></a><span class="lineno">  125</span>&#160;  }</div>
<div class="line"><a name="l00126"></a><span class="lineno">  126</span>&#160; </div>
<div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160;  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> T&gt;</div>
<div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> fill(T* begin, T* <a class="codeRef" href="../group__Core__Module.html#ga0e45b6b2adead7c6a29815b99f9f14dd">end</a>, <span class="keyword">const</span> T&amp; value)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00129"></a><span class="lineno">  129</span>&#160;    std::fill(begin, <a class="codeRef" href="../group__Core__Module.html#ga0e45b6b2adead7c6a29815b99f9f14dd">end</a>, value);</div>
<div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160;  }</div>
<div class="line"><a name="l00131"></a><span class="lineno">  131</span>&#160; </div>
<div class="line"><a name="l00132"></a><span class="lineno">  132</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">int</span> numThreads()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00133"></a><span class="lineno">  133</span>&#160;    <span class="keywordflow">return</span> num_threads_;</div>
<div class="line"><a name="l00134"></a><span class="lineno">  134</span>&#160;  }</div>
<div class="line"><a name="l00135"></a><span class="lineno">  135</span>&#160; </div>
<div class="line"><a name="l00136"></a><span class="lineno">  136</span>&#160;  <span class="comment">// Number of theads available in the underlying thread pool. This number can</span></div>
<div class="line"><a name="l00137"></a><span class="lineno">  137</span>&#160;  <span class="comment">// be different from the value returned by numThreads().</span></div>
<div class="line"><a name="l00138"></a><span class="lineno">  138</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">int</span> numThreadsInPool()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00139"></a><span class="lineno">  139</span>&#160;    <span class="keywordflow">return</span> pool_-&gt;NumThreads();</div>
<div class="line"><a name="l00140"></a><span class="lineno">  140</span>&#160;  }</div>
<div class="line"><a name="l00141"></a><span class="lineno">  141</span>&#160; </div>
<div class="line"><a name="l00142"></a><span class="lineno">  142</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">size_t</span> firstLevelCacheSize()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00143"></a><span class="lineno">  143</span>&#160;    <span class="keywordflow">return</span> l1CacheSize();</div>
<div class="line"><a name="l00144"></a><span class="lineno">  144</span>&#160;  }</div>
<div class="line"><a name="l00145"></a><span class="lineno">  145</span>&#160; </div>
<div class="line"><a name="l00146"></a><span class="lineno">  146</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">size_t</span> lastLevelCacheSize()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00147"></a><span class="lineno">  147</span>&#160;    <span class="comment">// The l3 cache size is shared between all the cores.</span></div>
<div class="line"><a name="l00148"></a><span class="lineno">  148</span>&#160;    <span class="keywordflow">return</span> l3CacheSize() / num_threads_;</div>
<div class="line"><a name="l00149"></a><span class="lineno">  149</span>&#160;  }</div>
<div class="line"><a name="l00150"></a><span class="lineno">  150</span>&#160; </div>
<div class="line"><a name="l00151"></a><span class="lineno">  151</span>&#160;  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE <span class="keywordtype">int</span> majorDeviceVersion()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00152"></a><span class="lineno">  152</span>&#160;    <span class="comment">// Should return an enum that encodes the ISA supported by the CPU</span></div>
<div class="line"><a name="l00153"></a><span class="lineno">  153</span>&#160;    <span class="keywordflow">return</span> 1;</div>
<div class="line"><a name="l00154"></a><span class="lineno">  154</span>&#160;  }</div>
<div class="line"><a name="l00155"></a><span class="lineno">  155</span>&#160; </div>
<div class="line"><a name="l00156"></a><span class="lineno">  156</span>&#160;  <span class="keyword">template</span> &lt;<span class="keyword">class </span>Function, <span class="keyword">class</span>... Args&gt;</div>
<div class="line"><a name="l00157"></a><span class="lineno">  157</span>&#160;  EIGEN_STRONG_INLINE Notification* enqueue(Function&amp;&amp; f,</div>
<div class="line"><a name="l00158"></a><span class="lineno">  158</span>&#160;                                            Args&amp;&amp;... args)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00159"></a><span class="lineno">  159</span>&#160;    Notification* n = <span class="keyword">new</span> Notification();</div>
<div class="line"><a name="l00160"></a><span class="lineno">  160</span>&#160;    pool_-&gt;Schedule(</div>
<div class="line"><a name="l00161"></a><span class="lineno">  161</span>&#160;        std::bind(&amp;FunctionWrapperWithNotification&lt;Function, Args...&gt;::run, n,</div>
<div class="line"><a name="l00162"></a><span class="lineno">  162</span>&#160;                  std::move(f), args...));</div>
<div class="line"><a name="l00163"></a><span class="lineno">  163</span>&#160;    <span class="keywordflow">return</span> n;</div>
<div class="line"><a name="l00164"></a><span class="lineno">  164</span>&#160;  }</div>
<div class="line"><a name="l00165"></a><span class="lineno">  165</span>&#160; </div>
<div class="line"><a name="l00166"></a><span class="lineno">  166</span>&#160;  <span class="keyword">template</span> &lt;<span class="keyword">class </span>Function, <span class="keyword">class</span>... Args&gt;</div>
<div class="line"><a name="l00167"></a><span class="lineno">  167</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> enqueue_with_barrier(Barrier* b, Function&amp;&amp; f,</div>
<div class="line"><a name="l00168"></a><span class="lineno">  168</span>&#160;                                                Args&amp;&amp;... args)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00169"></a><span class="lineno">  169</span>&#160;    pool_-&gt;Schedule(</div>
<div class="line"><a name="l00170"></a><span class="lineno">  170</span>&#160;        std::bind(&amp;FunctionWrapperWithBarrier&lt;Function, Args...&gt;::run, b,</div>
<div class="line"><a name="l00171"></a><span class="lineno">  171</span>&#160;                  std::move(f), args...));</div>
<div class="line"><a name="l00172"></a><span class="lineno">  172</span>&#160;  }</div>
<div class="line"><a name="l00173"></a><span class="lineno">  173</span>&#160; </div>
<div class="line"><a name="l00174"></a><span class="lineno">  174</span>&#160;  <span class="keyword">template</span> &lt;<span class="keyword">class </span>Function, <span class="keyword">class</span>... Args&gt;</div>
<div class="line"><a name="l00175"></a><span class="lineno">  175</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">void</span> enqueueNoNotification(Function&amp;&amp; f,</div>
<div class="line"><a name="l00176"></a><span class="lineno">  176</span>&#160;                                                 Args&amp;&amp;... args)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00177"></a><span class="lineno">  177</span>&#160;    <span class="keywordflow">if</span> (<span class="keyword">sizeof</span>...(args) &gt; 0) {</div>
<div class="line"><a name="l00178"></a><span class="lineno">  178</span>&#160;      pool_-&gt;Schedule(std::bind(std::move(f), args...));</div>
<div class="line"><a name="l00179"></a><span class="lineno">  179</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00180"></a><span class="lineno">  180</span>&#160;      pool_-&gt;Schedule(std::move(f));</div>
<div class="line"><a name="l00181"></a><span class="lineno">  181</span>&#160;    }</div>
<div class="line"><a name="l00182"></a><span class="lineno">  182</span>&#160;  }</div>
<div class="line"><a name="l00183"></a><span class="lineno">  183</span>&#160; </div>
<div class="line"><a name="l00184"></a><span class="lineno">  184</span>&#160;  <span class="comment">// Returns a logical thread index between 0 and pool_-&gt;NumThreads() - 1 if</span></div>
<div class="line"><a name="l00185"></a><span class="lineno">  185</span>&#160;  <span class="comment">// called from one of the threads in pool_. Returns -1 otherwise.</span></div>
<div class="line"><a name="l00186"></a><span class="lineno">  186</span>&#160;  EIGEN_STRONG_INLINE <span class="keywordtype">int</span> currentThreadId()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00187"></a><span class="lineno">  187</span>&#160;    <span class="keywordflow">return</span> pool_-&gt;CurrentThreadId();</div>
<div class="line"><a name="l00188"></a><span class="lineno">  188</span>&#160;  }</div>
<div class="line"><a name="l00189"></a><span class="lineno">  189</span>&#160; </div>
<div class="line"><a name="l00190"></a><span class="lineno">  190</span>&#160;  <span class="comment">// WARNING: This function is synchronous and will block the calling thread.</span></div>
<div class="line"><a name="l00191"></a><span class="lineno">  191</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00192"></a><span class="lineno">  192</span>&#160;  <span class="comment">// Synchronous parallelFor executes f with [0, n) arguments in parallel and</span></div>
<div class="line"><a name="l00193"></a><span class="lineno">  193</span>&#160;  <span class="comment">// waits for completion. F accepts a half-open interval [first, last). Block</span></div>
<div class="line"><a name="l00194"></a><span class="lineno">  194</span>&#160;  <span class="comment">// size is chosen based on the iteration cost and resulting parallel</span></div>
<div class="line"><a name="l00195"></a><span class="lineno">  195</span>&#160;  <span class="comment">// efficiency. If block_align is not nullptr, it is called to round up the</span></div>
<div class="line"><a name="l00196"></a><span class="lineno">  196</span>&#160;  <span class="comment">// block size.</span></div>
<div class="line"><a name="l00197"></a><span class="lineno">  197</span>&#160;  <span class="keywordtype">void</span> parallelFor(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> n, <span class="keyword">const</span> TensorOpCost&amp; cost,</div>
<div class="line"><a name="l00198"></a><span class="lineno">  198</span>&#160;                   std::function&lt;<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; block_align,</div>
<div class="line"><a name="l00199"></a><span class="lineno">  199</span>&#160;                   std::function&lt;<span class="keywordtype">void</span>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; f)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00200"></a><span class="lineno">  200</span>&#160;    <span class="keywordflow">if</span> (EIGEN_PREDICT_FALSE(n &lt;= 0)){</div>
<div class="line"><a name="l00201"></a><span class="lineno">  201</span>&#160;      <span class="keywordflow">return</span>;</div>
<div class="line"><a name="l00202"></a><span class="lineno">  202</span>&#160;    <span class="comment">// Compute small problems directly in the caller thread.</span></div>
<div class="line"><a name="l00203"></a><span class="lineno">  203</span>&#160;    } <span class="keywordflow">else</span> <span class="keywordflow">if</span> (n == 1 || numThreads() == 1 ||</div>
<div class="line"><a name="l00204"></a><span class="lineno">  204</span>&#160;               CostModel::numThreads(n, cost, <span class="keyword">static_cast&lt;</span><span class="keywordtype">int</span><span class="keyword">&gt;</span>(numThreads())) == 1) {</div>
<div class="line"><a name="l00205"></a><span class="lineno">  205</span>&#160;      f(0, n);</div>
<div class="line"><a name="l00206"></a><span class="lineno">  206</span>&#160;      <span class="keywordflow">return</span>;</div>
<div class="line"><a name="l00207"></a><span class="lineno">  207</span>&#160;    }</div>
<div class="line"><a name="l00208"></a><span class="lineno">  208</span>&#160; </div>
<div class="line"><a name="l00209"></a><span class="lineno">  209</span>&#160;    <span class="comment">// Compute block size and total count of blocks.</span></div>
<div class="line"><a name="l00210"></a><span class="lineno">  210</span>&#160;    ParallelForBlock block = CalculateParallelForBlock(n, cost, block_align);</div>
<div class="line"><a name="l00211"></a><span class="lineno">  211</span>&#160; </div>
<div class="line"><a name="l00212"></a><span class="lineno">  212</span>&#160;    <span class="comment">// Recursively divide size into halves until we reach block_size.</span></div>
<div class="line"><a name="l00213"></a><span class="lineno">  213</span>&#160;    <span class="comment">// Division code rounds mid to block_size, so we are guaranteed to get</span></div>
<div class="line"><a name="l00214"></a><span class="lineno">  214</span>&#160;    <span class="comment">// block_count leaves that do actual computations.</span></div>
<div class="line"><a name="l00215"></a><span class="lineno">  215</span>&#160;    Barrier barrier(<span class="keyword">static_cast&lt;</span><span class="keywordtype">unsigned</span> <span class="keywordtype">int</span><span class="keyword">&gt;</span>(block.count));</div>
<div class="line"><a name="l00216"></a><span class="lineno">  216</span>&#160;    std::function&lt;void(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; handleRange;</div>
<div class="line"><a name="l00217"></a><span class="lineno">  217</span>&#160;    handleRange = [=, &amp;handleRange, &amp;barrier, &amp;f](<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> firstIdx,</div>
<div class="line"><a name="l00218"></a><span class="lineno">  218</span>&#160;                                                  <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> lastIdx) {</div>
<div class="line"><a name="l00219"></a><span class="lineno">  219</span>&#160;      <span class="keywordflow">while</span> (lastIdx - firstIdx &gt; block.size) {</div>
<div class="line"><a name="l00220"></a><span class="lineno">  220</span>&#160;        <span class="comment">// Split into halves and schedule the second half on a different thread.</span></div>
<div class="line"><a name="l00221"></a><span class="lineno">  221</span>&#160;        <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> midIdx = firstIdx + divup((lastIdx - firstIdx) / 2, block.size) * block.size;</div>
<div class="line"><a name="l00222"></a><span class="lineno">  222</span>&#160;        pool_-&gt;Schedule([=, &amp;handleRange]() { handleRange(midIdx, lastIdx); });</div>
<div class="line"><a name="l00223"></a><span class="lineno">  223</span>&#160;        lastIdx = midIdx;</div>
<div class="line"><a name="l00224"></a><span class="lineno">  224</span>&#160;      }</div>
<div class="line"><a name="l00225"></a><span class="lineno">  225</span>&#160;      <span class="comment">// Single block or less, execute directly.</span></div>
<div class="line"><a name="l00226"></a><span class="lineno">  226</span>&#160;      f(firstIdx, lastIdx);</div>
<div class="line"><a name="l00227"></a><span class="lineno">  227</span>&#160;      barrier.Notify();</div>
<div class="line"><a name="l00228"></a><span class="lineno">  228</span>&#160;    };</div>
<div class="line"><a name="l00229"></a><span class="lineno">  229</span>&#160; </div>
<div class="line"><a name="l00230"></a><span class="lineno">  230</span>&#160;    <span class="keywordflow">if</span> (block.count &lt;= numThreads()) {</div>
<div class="line"><a name="l00231"></a><span class="lineno">  231</span>&#160;      <span class="comment">// Avoid a thread hop by running the root of the tree and one block on the</span></div>
<div class="line"><a name="l00232"></a><span class="lineno">  232</span>&#160;      <span class="comment">// main thread.</span></div>
<div class="line"><a name="l00233"></a><span class="lineno">  233</span>&#160;      handleRange(0, n);</div>
<div class="line"><a name="l00234"></a><span class="lineno">  234</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00235"></a><span class="lineno">  235</span>&#160;      <span class="comment">// Execute the root in the thread pool to avoid running work on more than</span></div>
<div class="line"><a name="l00236"></a><span class="lineno">  236</span>&#160;      <span class="comment">// numThreads() threads.</span></div>
<div class="line"><a name="l00237"></a><span class="lineno">  237</span>&#160;      pool_-&gt;Schedule([=, &amp;handleRange]() { handleRange(0, n); });</div>
<div class="line"><a name="l00238"></a><span class="lineno">  238</span>&#160;    }</div>
<div class="line"><a name="l00239"></a><span class="lineno">  239</span>&#160; </div>
<div class="line"><a name="l00240"></a><span class="lineno">  240</span>&#160;    barrier.Wait();</div>
<div class="line"><a name="l00241"></a><span class="lineno">  241</span>&#160;  }</div>
<div class="line"><a name="l00242"></a><span class="lineno">  242</span>&#160; </div>
<div class="line"><a name="l00243"></a><span class="lineno">  243</span>&#160;  <span class="comment">// Convenience wrapper for parallelFor that does not align blocks.</span></div>
<div class="line"><a name="l00244"></a><span class="lineno">  244</span>&#160;  <span class="keywordtype">void</span> parallelFor(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> n, <span class="keyword">const</span> TensorOpCost&amp; cost,</div>
<div class="line"><a name="l00245"></a><span class="lineno">  245</span>&#160;                   std::function&lt;<span class="keywordtype">void</span>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; f)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00246"></a><span class="lineno">  246</span>&#160;    parallelFor(n, cost, <span class="keyword">nullptr</span>, std::move(f));</div>
<div class="line"><a name="l00247"></a><span class="lineno">  247</span>&#160;  }</div>
<div class="line"><a name="l00248"></a><span class="lineno">  248</span>&#160; </div>
<div class="line"><a name="l00249"></a><span class="lineno">  249</span>&#160;  <span class="comment">// WARNING: This function is asynchronous and will not block the calling thread.</span></div>
<div class="line"><a name="l00250"></a><span class="lineno">  250</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00251"></a><span class="lineno">  251</span>&#160;  <span class="comment">// Asynchronous parallelFor executes f with [0, n) arguments in parallel</span></div>
<div class="line"><a name="l00252"></a><span class="lineno">  252</span>&#160;  <span class="comment">// without waiting for completion. When the last block finished, it will call</span></div>
<div class="line"><a name="l00253"></a><span class="lineno">  253</span>&#160;  <span class="comment">// &#39;done&#39; callback. F accepts a half-open interval [first, last). Block size</span></div>
<div class="line"><a name="l00254"></a><span class="lineno">  254</span>&#160;  <span class="comment">// is chosen based on the iteration cost and resulting parallel efficiency. If</span></div>
<div class="line"><a name="l00255"></a><span class="lineno">  255</span>&#160;  <span class="comment">// block_align is not nullptr, it is called to round up the block size.</span></div>
<div class="line"><a name="l00256"></a><span class="lineno">  256</span>&#160;  <span class="keywordtype">void</span> parallelForAsync(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> n, <span class="keyword">const</span> TensorOpCost&amp; cost,</div>
<div class="line"><a name="l00257"></a><span class="lineno">  257</span>&#160;                        std::function&lt;<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; block_align,</div>
<div class="line"><a name="l00258"></a><span class="lineno">  258</span>&#160;                        std::function&lt;<span class="keywordtype">void</span>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; f,</div>
<div class="line"><a name="l00259"></a><span class="lineno">  259</span>&#160;                        std::function&lt;<span class="keywordtype">void</span>()&gt; done)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00260"></a><span class="lineno">  260</span>&#160;    <span class="comment">// Compute small problems directly in the caller thread.</span></div>
<div class="line"><a name="l00261"></a><span class="lineno">  261</span>&#160;    <span class="keywordflow">if</span> (n &lt;= 1 || numThreads() == 1 ||</div>
<div class="line"><a name="l00262"></a><span class="lineno">  262</span>&#160;        CostModel::numThreads(n, cost, <span class="keyword">static_cast&lt;</span><span class="keywordtype">int</span><span class="keyword">&gt;</span>(numThreads())) == 1) {</div>
<div class="line"><a name="l00263"></a><span class="lineno">  263</span>&#160;      f(0, n);</div>
<div class="line"><a name="l00264"></a><span class="lineno">  264</span>&#160;      done();</div>
<div class="line"><a name="l00265"></a><span class="lineno">  265</span>&#160;      <span class="keywordflow">return</span>;</div>
<div class="line"><a name="l00266"></a><span class="lineno">  266</span>&#160;    }</div>
<div class="line"><a name="l00267"></a><span class="lineno">  267</span>&#160; </div>
<div class="line"><a name="l00268"></a><span class="lineno">  268</span>&#160;    <span class="comment">// Compute block size and total count of blocks.</span></div>
<div class="line"><a name="l00269"></a><span class="lineno">  269</span>&#160;    ParallelForBlock block = CalculateParallelForBlock(n, cost, block_align);</div>
<div class="line"><a name="l00270"></a><span class="lineno">  270</span>&#160; </div>
<div class="line"><a name="l00271"></a><span class="lineno">  271</span>&#160;    ParallelForAsyncContext* <span class="keyword">const</span> ctx =</div>
<div class="line"><a name="l00272"></a><span class="lineno">  272</span>&#160;        <span class="keyword">new</span> ParallelForAsyncContext(block.count, std::move(f), std::move(done));</div>
<div class="line"><a name="l00273"></a><span class="lineno">  273</span>&#160; </div>
<div class="line"><a name="l00274"></a><span class="lineno">  274</span>&#160;    <span class="comment">// Recursively divide size into halves until we reach block_size.</span></div>
<div class="line"><a name="l00275"></a><span class="lineno">  275</span>&#160;    <span class="comment">// Division code rounds mid to block_size, so we are guaranteed to get</span></div>
<div class="line"><a name="l00276"></a><span class="lineno">  276</span>&#160;    <span class="comment">// block_count leaves that do actual computations.</span></div>
<div class="line"><a name="l00277"></a><span class="lineno">  277</span>&#160;    ctx-&gt;handle_range = [<span class="keyword">this</span>, ctx, block](<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> firstIdx, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> lastIdx) {</div>
<div class="line"><a name="l00278"></a><span class="lineno">  278</span>&#160;      <span class="keywordflow">while</span> (lastIdx - firstIdx &gt; block.size) {</div>
<div class="line"><a name="l00279"></a><span class="lineno">  279</span>&#160;        <span class="comment">// Split into halves and schedule the second half on a different thread.</span></div>
<div class="line"><a name="l00280"></a><span class="lineno">  280</span>&#160;        <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> midIdx = firstIdx + divup((lastIdx - firstIdx) / 2, block.size) * block.size;</div>
<div class="line"><a name="l00281"></a><span class="lineno">  281</span>&#160;        pool_-&gt;Schedule(</div>
<div class="line"><a name="l00282"></a><span class="lineno">  282</span>&#160;            [ctx, midIdx, lastIdx]() { ctx-&gt;handle_range(midIdx, lastIdx); });</div>
<div class="line"><a name="l00283"></a><span class="lineno">  283</span>&#160;        lastIdx = midIdx;</div>
<div class="line"><a name="l00284"></a><span class="lineno">  284</span>&#160;      }</div>
<div class="line"><a name="l00285"></a><span class="lineno">  285</span>&#160; </div>
<div class="line"><a name="l00286"></a><span class="lineno">  286</span>&#160;      <span class="comment">// Single block or less, execute directly.</span></div>
<div class="line"><a name="l00287"></a><span class="lineno">  287</span>&#160;      ctx-&gt;f(firstIdx, lastIdx);</div>
<div class="line"><a name="l00288"></a><span class="lineno">  288</span>&#160; </div>
<div class="line"><a name="l00289"></a><span class="lineno">  289</span>&#160;      <span class="comment">// Delete async context if it was the last block.</span></div>
<div class="line"><a name="l00290"></a><span class="lineno">  290</span>&#160;      <span class="keywordflow">if</span> (ctx-&gt;count.fetch_sub(1) == 1) <span class="keyword">delete</span> ctx;</div>
<div class="line"><a name="l00291"></a><span class="lineno">  291</span>&#160;    };</div>
<div class="line"><a name="l00292"></a><span class="lineno">  292</span>&#160; </div>
<div class="line"><a name="l00293"></a><span class="lineno">  293</span>&#160;    <span class="keywordflow">if</span> (block.count &lt;= numThreads()) {</div>
<div class="line"><a name="l00294"></a><span class="lineno">  294</span>&#160;      <span class="comment">// Avoid a thread hop by running the root of the tree and one block on the</span></div>
<div class="line"><a name="l00295"></a><span class="lineno">  295</span>&#160;      <span class="comment">// main thread.</span></div>
<div class="line"><a name="l00296"></a><span class="lineno">  296</span>&#160;      ctx-&gt;handle_range(0, n);</div>
<div class="line"><a name="l00297"></a><span class="lineno">  297</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00298"></a><span class="lineno">  298</span>&#160;      <span class="comment">// Execute the root in the thread pool to avoid running work on more than</span></div>
<div class="line"><a name="l00299"></a><span class="lineno">  299</span>&#160;      <span class="comment">// numThreads() threads.</span></div>
<div class="line"><a name="l00300"></a><span class="lineno">  300</span>&#160;      pool_-&gt;Schedule([ctx, n]() { ctx-&gt;handle_range(0, n); });</div>
<div class="line"><a name="l00301"></a><span class="lineno">  301</span>&#160;    }</div>
<div class="line"><a name="l00302"></a><span class="lineno">  302</span>&#160;  }</div>
<div class="line"><a name="l00303"></a><span class="lineno">  303</span>&#160; </div>
<div class="line"><a name="l00304"></a><span class="lineno">  304</span>&#160;  <span class="comment">// Convenience wrapper for parallelForAsync that does not align blocks.</span></div>
<div class="line"><a name="l00305"></a><span class="lineno">  305</span>&#160;  <span class="keywordtype">void</span> parallelForAsync(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> n, <span class="keyword">const</span> TensorOpCost&amp; cost,</div>
<div class="line"><a name="l00306"></a><span class="lineno">  306</span>&#160;                        std::function&lt;<span class="keywordtype">void</span>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; f,</div>
<div class="line"><a name="l00307"></a><span class="lineno">  307</span>&#160;                        std::function&lt;<span class="keywordtype">void</span>()&gt; done)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00308"></a><span class="lineno">  308</span>&#160;    parallelForAsync(n, cost, <span class="keyword">nullptr</span>, std::move(f), std::move(done));</div>
<div class="line"><a name="l00309"></a><span class="lineno">  309</span>&#160;  }</div>
<div class="line"><a name="l00310"></a><span class="lineno">  310</span>&#160; </div>
<div class="line"><a name="l00311"></a><span class="lineno">  311</span>&#160;  <span class="comment">// Thread pool accessor.</span></div>
<div class="line"><a name="l00312"></a><span class="lineno">  312</span>&#160;  ThreadPoolInterface* getPool()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> pool_; }</div>
<div class="line"><a name="l00313"></a><span class="lineno">  313</span>&#160; </div>
<div class="line"><a name="l00314"></a><span class="lineno">  314</span>&#160;  <span class="comment">// Allocator accessor.</span></div>
<div class="line"><a name="l00315"></a><span class="lineno">  315</span>&#160;  Allocator* allocator()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> allocator_; }</div>
<div class="line"><a name="l00316"></a><span class="lineno">  316</span>&#160; </div>
<div class="line"><a name="l00317"></a><span class="lineno">  317</span>&#160; <span class="keyword">private</span>:</div>
<div class="line"><a name="l00318"></a><span class="lineno">  318</span>&#160;  <span class="keyword">typedef</span> TensorCostModel&lt;ThreadPoolDevice&gt; CostModel;</div>
<div class="line"><a name="l00319"></a><span class="lineno">  319</span>&#160; </div>
<div class="line"><a name="l00320"></a><span class="lineno">  320</span>&#160;  <span class="comment">// For parallelForAsync we must keep passed in closures on the heap, and</span></div>
<div class="line"><a name="l00321"></a><span class="lineno">  321</span>&#160;  <span class="comment">// delete them only after `done` callback finished.</span></div>
<div class="line"><a name="l00322"></a><span class="lineno">  322</span>&#160;  <span class="keyword">struct </span>ParallelForAsyncContext {</div>
<div class="line"><a name="l00323"></a><span class="lineno">  323</span>&#160;    ParallelForAsyncContext(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> block_count,</div>
<div class="line"><a name="l00324"></a><span class="lineno">  324</span>&#160;                            std::function&lt;<span class="keywordtype">void</span>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; block_f,</div>
<div class="line"><a name="l00325"></a><span class="lineno">  325</span>&#160;                            std::function&lt;<span class="keywordtype">void</span>()&gt; done_callback)</div>
<div class="line"><a name="l00326"></a><span class="lineno">  326</span>&#160;        : count(block_count),</div>
<div class="line"><a name="l00327"></a><span class="lineno">  327</span>&#160;          f(std::move(block_f)),</div>
<div class="line"><a name="l00328"></a><span class="lineno">  328</span>&#160;          done(std::move(done_callback)) {}</div>
<div class="line"><a name="l00329"></a><span class="lineno">  329</span>&#160;    ~ParallelForAsyncContext() { done(); }</div>
<div class="line"><a name="l00330"></a><span class="lineno">  330</span>&#160; </div>
<div class="line"><a name="l00331"></a><span class="lineno">  331</span>&#160;    std::atomic&lt;Index&gt; count;</div>
<div class="line"><a name="l00332"></a><span class="lineno">  332</span>&#160;    std::function&lt;void(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; f;</div>
<div class="line"><a name="l00333"></a><span class="lineno">  333</span>&#160;    std::function&lt;void()&gt; done;</div>
<div class="line"><a name="l00334"></a><span class="lineno">  334</span>&#160; </div>
<div class="line"><a name="l00335"></a><span class="lineno">  335</span>&#160;    std::function&lt;void(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>, <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; handle_range;</div>
<div class="line"><a name="l00336"></a><span class="lineno">  336</span>&#160;  };</div>
<div class="line"><a name="l00337"></a><span class="lineno">  337</span>&#160; </div>
<div class="line"><a name="l00338"></a><span class="lineno">  338</span>&#160;  <span class="keyword">struct </span>ParallelForBlock {</div>
<div class="line"><a name="l00339"></a><span class="lineno">  339</span>&#160;    <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> size;   <span class="comment">// block size</span></div>
<div class="line"><a name="l00340"></a><span class="lineno">  340</span>&#160;    <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> count;  <span class="comment">// number of blocks</span></div>
<div class="line"><a name="l00341"></a><span class="lineno">  341</span>&#160;  };</div>
<div class="line"><a name="l00342"></a><span class="lineno">  342</span>&#160; </div>
<div class="line"><a name="l00343"></a><span class="lineno">  343</span>&#160;  <span class="comment">// Calculates block size based on (1) the iteration cost and (2) parallel</span></div>
<div class="line"><a name="l00344"></a><span class="lineno">  344</span>&#160;  <span class="comment">// efficiency. We want blocks to be not too small to mitigate parallelization</span></div>
<div class="line"><a name="l00345"></a><span class="lineno">  345</span>&#160;  <span class="comment">// overheads; not too large to mitigate tail effect and potential load</span></div>
<div class="line"><a name="l00346"></a><span class="lineno">  346</span>&#160;  <span class="comment">// imbalance and we also want number of blocks to be evenly dividable across</span></div>
<div class="line"><a name="l00347"></a><span class="lineno">  347</span>&#160;  <span class="comment">// threads.</span></div>
<div class="line"><a name="l00348"></a><span class="lineno">  348</span>&#160;  ParallelForBlock CalculateParallelForBlock(</div>
<div class="line"><a name="l00349"></a><span class="lineno">  349</span>&#160;      <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> n, <span class="keyword">const</span> TensorOpCost&amp; cost,</div>
<div class="line"><a name="l00350"></a><span class="lineno">  350</span>&#160;      std::function&lt;<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>(<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a>)&gt; block_align)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00351"></a><span class="lineno">  351</span>&#160;    <span class="keyword">const</span> <span class="keywordtype">double</span> block_size_f = 1.0 / CostModel::taskSize(1, cost);</div>
<div class="line"><a name="l00352"></a><span class="lineno">  352</span>&#160;    <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> max_oversharding_factor = 4;</div>
<div class="line"><a name="l00353"></a><span class="lineno">  353</span>&#160;    <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> block_size = numext::mini(</div>
<div class="line"><a name="l00354"></a><span class="lineno">  354</span>&#160;        n, numext::maxi&lt;Index&gt;(</div>
<div class="line"><a name="l00355"></a><span class="lineno">  355</span>&#160;               divup&lt;Index&gt;(n, max_oversharding_factor * numThreads()),</div>
<div class="line"><a name="l00356"></a><span class="lineno">  356</span>&#160;               block_size_f));</div>
<div class="line"><a name="l00357"></a><span class="lineno">  357</span>&#160;    <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> max_block_size = numext::mini(n, 2 * block_size);</div>
<div class="line"><a name="l00358"></a><span class="lineno">  358</span>&#160; </div>
<div class="line"><a name="l00359"></a><span class="lineno">  359</span>&#160;    <span class="keywordflow">if</span> (block_align) {</div>
<div class="line"><a name="l00360"></a><span class="lineno">  360</span>&#160;      <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> new_block_size = block_align(block_size);</div>
<div class="line"><a name="l00361"></a><span class="lineno">  361</span>&#160;      eigen_assert(new_block_size &gt;= block_size);</div>
<div class="line"><a name="l00362"></a><span class="lineno">  362</span>&#160;      block_size = numext::mini(n, new_block_size);</div>
<div class="line"><a name="l00363"></a><span class="lineno">  363</span>&#160;    }</div>
<div class="line"><a name="l00364"></a><span class="lineno">  364</span>&#160; </div>
<div class="line"><a name="l00365"></a><span class="lineno">  365</span>&#160;    <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> block_count = divup(n, block_size);</div>
<div class="line"><a name="l00366"></a><span class="lineno">  366</span>&#160; </div>
<div class="line"><a name="l00367"></a><span class="lineno">  367</span>&#160;    <span class="comment">// Calculate parallel efficiency as fraction of total CPU time used for</span></div>
<div class="line"><a name="l00368"></a><span class="lineno">  368</span>&#160;    <span class="comment">// computations:</span></div>
<div class="line"><a name="l00369"></a><span class="lineno">  369</span>&#160;    <span class="keywordtype">double</span> max_efficiency =</div>
<div class="line"><a name="l00370"></a><span class="lineno">  370</span>&#160;        <span class="keyword">static_cast&lt;</span><span class="keywordtype">double</span><span class="keyword">&gt;</span>(block_count) /</div>
<div class="line"><a name="l00371"></a><span class="lineno">  371</span>&#160;        (divup&lt;int&gt;(block_count, numThreads()) * numThreads());</div>
<div class="line"><a name="l00372"></a><span class="lineno">  372</span>&#160; </div>
<div class="line"><a name="l00373"></a><span class="lineno">  373</span>&#160;    <span class="comment">// Now try to increase block size up to max_block_size as long as it</span></div>
<div class="line"><a name="l00374"></a><span class="lineno">  374</span>&#160;    <span class="comment">// doesn&#39;t decrease parallel efficiency.</span></div>
<div class="line"><a name="l00375"></a><span class="lineno">  375</span>&#160;    <span class="keywordflow">for</span> (<a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> prev_block_count = block_count;</div>
<div class="line"><a name="l00376"></a><span class="lineno">  376</span>&#160;         max_efficiency &lt; 1.0 &amp;&amp; prev_block_count &gt; 1;) {</div>
<div class="line"><a name="l00377"></a><span class="lineno">  377</span>&#160;      <span class="comment">// This is the next block size that divides size into a smaller number</span></div>
<div class="line"><a name="l00378"></a><span class="lineno">  378</span>&#160;      <span class="comment">// of blocks than the current block_size.</span></div>
<div class="line"><a name="l00379"></a><span class="lineno">  379</span>&#160;      <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> coarser_block_size = divup(n, prev_block_count - 1);</div>
<div class="line"><a name="l00380"></a><span class="lineno">  380</span>&#160;      <span class="keywordflow">if</span> (block_align) {</div>
<div class="line"><a name="l00381"></a><span class="lineno">  381</span>&#160;        <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> new_block_size = block_align(coarser_block_size);</div>
<div class="line"><a name="l00382"></a><span class="lineno">  382</span>&#160;        eigen_assert(new_block_size &gt;= coarser_block_size);</div>
<div class="line"><a name="l00383"></a><span class="lineno">  383</span>&#160;        coarser_block_size = numext::mini(n, new_block_size);</div>
<div class="line"><a name="l00384"></a><span class="lineno">  384</span>&#160;      }</div>
<div class="line"><a name="l00385"></a><span class="lineno">  385</span>&#160;      <span class="keywordflow">if</span> (coarser_block_size &gt; max_block_size) {</div>
<div class="line"><a name="l00386"></a><span class="lineno">  386</span>&#160;        <span class="keywordflow">break</span>;  <span class="comment">// Reached max block size. Stop.</span></div>
<div class="line"><a name="l00387"></a><span class="lineno">  387</span>&#160;      }</div>
<div class="line"><a name="l00388"></a><span class="lineno">  388</span>&#160;      <span class="comment">// Recalculate parallel efficiency.</span></div>
<div class="line"><a name="l00389"></a><span class="lineno">  389</span>&#160;      <span class="keyword">const</span> <a class="codeRef" href="../namespaceEigen.html#a62e77e0933482dafde8fe197d9a2cfde">Index</a> coarser_block_count = divup(n, coarser_block_size);</div>
<div class="line"><a name="l00390"></a><span class="lineno">  390</span>&#160;      eigen_assert(coarser_block_count &lt; prev_block_count);</div>
<div class="line"><a name="l00391"></a><span class="lineno">  391</span>&#160;      prev_block_count = coarser_block_count;</div>
<div class="line"><a name="l00392"></a><span class="lineno">  392</span>&#160;      <span class="keyword">const</span> <span class="keywordtype">double</span> coarser_efficiency =</div>
<div class="line"><a name="l00393"></a><span class="lineno">  393</span>&#160;          <span class="keyword">static_cast&lt;</span><span class="keywordtype">double</span><span class="keyword">&gt;</span>(coarser_block_count) /</div>
<div class="line"><a name="l00394"></a><span class="lineno">  394</span>&#160;          (divup&lt;int&gt;(coarser_block_count, numThreads()) * numThreads());</div>
<div class="line"><a name="l00395"></a><span class="lineno">  395</span>&#160;      <span class="keywordflow">if</span> (coarser_efficiency + 0.01 &gt;= max_efficiency) {</div>
<div class="line"><a name="l00396"></a><span class="lineno">  396</span>&#160;        <span class="comment">// Taking it.</span></div>
<div class="line"><a name="l00397"></a><span class="lineno">  397</span>&#160;        block_size = coarser_block_size;</div>
<div class="line"><a name="l00398"></a><span class="lineno">  398</span>&#160;        block_count = coarser_block_count;</div>
<div class="line"><a name="l00399"></a><span class="lineno">  399</span>&#160;        <span class="keywordflow">if</span> (max_efficiency &lt; coarser_efficiency) {</div>
<div class="line"><a name="l00400"></a><span class="lineno">  400</span>&#160;          max_efficiency = coarser_efficiency;</div>
<div class="line"><a name="l00401"></a><span class="lineno">  401</span>&#160;        }</div>
<div class="line"><a name="l00402"></a><span class="lineno">  402</span>&#160;      }</div>
<div class="line"><a name="l00403"></a><span class="lineno">  403</span>&#160;    }</div>
<div class="line"><a name="l00404"></a><span class="lineno">  404</span>&#160; </div>
<div class="line"><a name="l00405"></a><span class="lineno">  405</span>&#160;    <span class="keywordflow">return</span> {block_size, block_count};</div>
<div class="line"><a name="l00406"></a><span class="lineno">  406</span>&#160;  }</div>
<div class="line"><a name="l00407"></a><span class="lineno">  407</span>&#160; </div>
<div class="line"><a name="l00408"></a><span class="lineno">  408</span>&#160;  ThreadPoolInterface* pool_;</div>
<div class="line"><a name="l00409"></a><span class="lineno">  409</span>&#160;  <span class="keywordtype">int</span> num_threads_;</div>
<div class="line"><a name="l00410"></a><span class="lineno">  410</span>&#160;  Allocator* allocator_;</div>
<div class="line"><a name="l00411"></a><span class="lineno">  411</span>&#160;};</div>
<div class="line"><a name="l00412"></a><span class="lineno">  412</span>&#160; </div>
<div class="line"><a name="l00413"></a><span class="lineno">  413</span>&#160; </div>
<div class="line"><a name="l00414"></a><span class="lineno">  414</span>&#160;}  <span class="comment">// end namespace Eigen</span></div>
<div class="line"><a name="l00415"></a><span class="lineno">  415</span>&#160; </div>
<div class="line"><a name="l00416"></a><span class="lineno">  416</span>&#160;<span class="preprocessor">#endif </span><span class="comment">// EIGEN_CXX11_TENSOR_TENSOR_DEVICE_THREAD_POOL_H</span></div>
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